Jesus speaks of the time the temple will be destroyed.
Many troubles will come, but don't listen when they say Jesus has returned.
Get out of the city when you see the temple defiled.
Powers will be shaken. The end is near then, but no one knows the exact time.
Stay awake and alert and watching.
I find it very likely that everything Jesus was talking about here was about the destruction of Jerusalem by the Romans in 70A.D. See verses 2-4 and 30. Some of it, especially in other Gospel accounts, also applies to Christ's final return, still in the future.